Identification of CpG islands in a physical map encompassing the Friedreich's ataxia locus

The Friedreich's ataxia locus has been previously assigned to chromosome 9q 13-21.1 by the demonstration of tight linkage to two anonymous DNA markers. MCT112 (Z greater than 80, theta = 0) and DR47 (Z greater than 50, theta = 0). The absence of recombination between these three loci has prevented the resolution of gene/probe order in this region, impeding strategies for gene isolation. We report physical mapping over a 4-Mb genomic interval, linking the markers MCT112 and DR47 on a common 460-kb NotI fragment and identifying 11 CpG islands in the 1.7-Mb interval most likely to contain the Friedreich's ataxia locus. Four of these islands were detected only by analysis of three YAC clones spanning a 700-kb interval including the MCT112/DR47 cluster. Without clear evidence of the precise location of the disease locus from recombination events, each of these regions must be considered as specifying a potential "candidate" sequence for the mutated gene.     

The embryo sac ofPodostemum subulatus (Podostemaceae) — a reinvestigation

The female gametophyte ontogeny inPodostemum subulatus is of the Apinagia type and not the Podostemum type as reported earlier. The independent existence of the Podostemum type in the family is questioned.     

Association of cyclic nucleotide phosphodiesterase of buffalo spermatozoa with sperm chromatin

Buffalo sperm heads contain more than 50% of the total cyclic AMP-phosphodiesterase activity (EC 3.1.4.17) present in spermatozoa. Its distribution in sperm heads revealed no activity in acrosome and other membrane structures present in the head. All the cyclic AMP-phosphodiesterase activity was found firmly bound to sperm chromatin which could not be solubilized. In addition to cyclic AMP, cyclic GMP was also hydrolysed by chromatin preparation. The rate of hydrolysis was 2.5-times more rapid with cyclic AMP than with cyclic GMP at their optimum pH of 7.5 and 8.0, respectively. The pH and heat stability profiles, inhibition studies and the effect of divalent metal ions indicated that the two activities are not associated with the same protein. Mixed substrate analysis showed two sites at which the hydrolysis of cyclic AMP and cyclic GMP is catalysed. Chromatin cyclic nucleotide phosphodiesterases exhibited kinetics typical of one enzyme species both for cyclic AMP (K m = 100 microM; V = 1.0 nmol/min per mg protein) and cyclic GMP (Km = 23 microM; V = 0.4 nmol/min per mg protein). Each cyclic nucleotide was found to be a competitive inhibitor of the hydrolysis of the other with a Ki value of 30.18 microM for cyclic AMP hydrolysis and 256 microM for cyclic GMP hydrolysis. Hill coefficients of 1.0 obtained in the presence of cyclic AMP for cyclic GMP hydrolysis and vice-versa indicated no allosteric interactions. It is suggested that chromatin cyclic nucleotide phosphodiesterase may have a role post fertilization in cell growth and differentiation with no role in sperm motility which is regulated by similar enzymes present in sperm flagella.     

Detection of conformational changes in Complex III of the respiratory chain by a maleimido spin label

Changes in the conformation of Complex III (CoQH₂-cytochromec reductase) of the mitochondrial respiratory chain were detected upon oxidoreduction using the nitroxide spin label, 3-(maleimidomethyl)-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl. EPR spectra of the spin label show a transition from a greater to a lesser degree of immobilization when the labeled enzyme, reduced either with ascorbate or sodium dithionite, is oxidized with potassium ferricyanide or ferricytochromec. These observations are interpreted to indicate that Complex III is more compact in the reduced state at least in the locality of the spin label. An apparent increase in the concentration of total spins during oxidation of the complex suggests change in the interaction between the spin label and other paramagnetic centers and not an oxidation of spin label, itself, since reduced free spin label could not be reoxidized. Addition of antimycin A had no effect on the EPR spectrum of the spin-labeled enzyme, indicating that this inhibitor does not initiate a conformational change in the region of the spin label. Experiments in which N-ethyl-[2-³H] maleimide was bound to Complex III show that binding occurs primarily to a subunit with a molecular weight of 45,000. Although no qualitative differences were observed, it was found that less radioactivity appears in samples reduced with dithionite than in those reduced with ascorbate. This difference appears to be caused by decomposition products of dithionite.     

Light microscopic features of the rete testis,the vas efferens,the epididymis and the vas deferens in the adult rhesus monkey

The present study was carried out to determine the detailed histological and cytological features of the excurrent ducts of the male reproductive system in the rhesus monkey. The excurrent ducts show a regional difference in their histological features. The use of some of these features as histological markers and their possible functional significance are discussed. The epithelial cells in the different components of the excurrent duct system possess cytological features which suggest their involvement in absorption and the secretion of different products into the lumen.     

Intracellular disposition of [3H]-cocaine, [3H]-norcocaine, [3H]-benzoylecgonine and [3H]-benzoylnorecgonine in the brain of rats

[³H]-cocaine, [³H]-norcocaine, [³H]-benzoylecgonine and [³H]-benzoylnorecgonine were administered i.c. in equi-potent pharmacologic doses and the intracellular disposition and metabolism of each drug determined. Norcocaine and cocaine rapidly entered and egressed from the brain so that 4.8–6.1% of the radioactivity present in brain at one minute was observed at 30 minutes. The highest levels of subcellular radioactivity were generally found in the microsomal plus supernatant, followed by the nuclear and shocked mitochondrial fractions. No apparent localization of the radioactivity occured in synaptic membranes. The brain/plasma (B/P) ratio curves for cocaine and norcocaine were similar; however, the norcocaine values were considerably higher at each time interval. Benzoylecgonine and benzoylnorecgonine had higher comparative B/P ratios than cocaine or norcocaine and persisted in brain for a longer period of time so that 0.6–2.1% of the radioactivity present in brain at 1 hour was detected at 24 hours. Cocaine and norcocaine were extensively metabolized to the benzoylmetabolites. Benzoylecgonine was metabolized to benzoylnorecgonine and benzoylnorecgonine was unmetabolized. The brain disposition data and B/P ratios agreed quite well with the overall pharmacologic action of cocaine and its metabolites.     

Effect of gibberellic Acid on crown gall tumor induction in aging primary pinto bean leaves

Gibberellic acid was tested for its effect on tumor induction by Agrobacterium tumefaciens in primary pinto bean (Phaseolus vulgaris) leaves in various stages of development. The hormone was found to promote tumor induction in partially aged leaves but did not effect tumor induction in very young leaves or in fully matured leaves. It is suggested that the natural loss of susceptibility to tumor induction in maturing pinto bean leaves is associated with a concomitant loss of endogenous gibberellins and/or a sensitivity to gibberellins.     

Dhanwantaram kashayam,an Ayurvedic polyherbal formulation,reduces oxidative radicals and reverts lipids profile towards normal in diabetic rats

BackgroundHyperglycemia and hyper oxidative stress are indicators of diabetes mellitus which is also accompanied with decreased levels of antioxidant enzymes. While oxidative stress is important in increasing insulin secretion and controlling blood sugar level at the same time excess oxidative stress leads to the destruction of beta cells of pancreas resulting in to low insulin production and hyperglycemia. A balance between the levels of oxidative radicals and insulin production is needed, but is not defined yet. Hyperglycemia also leads to hyperlipidemia which can contribute to various health conditions like cardiovascular diseases.ObjectivesThis study was designed to study the oxidative stress and lipid levels in diabetic rats. This also was designed to elucidate the effect of Dhanwantaram Kashayam, an Ayurvedic polyphenolic derived from plants on lipid metabolism and oxidative radical scavenging in diabetic rats.MethodsRats were made diabetic by injecting streptozotocin. Different enzymes involved in oxidative radical scavenging and lipid profiles including triglycerides, total cholesterol, free fatty acids and phospholipids were estimated using standard methods reported elsewhere.ResultsLevel of antioxidant enzymes were lower in diabetic rats compared to normal controls. Administration of Dhanwantaram Kashayam restored the enzyme activity as well as reduced levels of different lipids in diabetic rats.ConclusionsAdministration of Dhanwantaram Kashayam increased the activity levels of antioxidant enzymes and reduced the levels of total cholesterol, phospholipids and triglycerides. The results of this study point to the possibility of developing Dhanwantaram Kashayam as a dietary supplement which can alleviate the complications associated with diabetes or prevent them altogether.